Hardware encryption keyboards of self-serving banking terminals are responsible for handling users' banking passwords inputting and encryption processing. Hence, working keys and master keys of the banks are stored in core processing components of the keyboards. Those who with unlawful purposes may pry or probe into the keyboards to capture user passwords, or even to read working keys and master keys of the banks, in order to steal documents from the banks, putting the documents and money of users and banks at risk.
Generally, encryption keyboards include a probing detection and protection structure, and a probing detection and protection circuit. When physical probing is initiated to a keyboard, the probing detection and protection circuit outputs a self-destruct signal, to enable a self-destruct function of the encryption keyboard, thereby preventing the bad guys from stealing the documents.
As shown in FIG. 1, a conventional encryption keyboard includes: a keyboard panel 1, a lining plate 2, keys 3, a water-resistant silica gel layer 4, a main control board 8, and a bottom plate 9. The keyboard is assembled by stacking up these components in sequence. Due to lack of a protective structure in front of the keyboard, the main control board 8 may easily be accessible to the bad guys if they have some of the components 1 to 4 damaged. In this manner, information in the circuit of the main control board can be obtained, and information that is crucial to the safe use of the self-serving terminals, e.g., user inputted passwords, may be stolen.
Therefore, it is of great importance to provide an encryption keyboard with a detection